Particularly in the beverage industry, increasingly high demands are placed on hygiene when treating containers, particularly when filling and closing containers under sterile and/or aseptic conditions. Corresponding treatment machines or devices therefore often require that, during the treatment, the container, or at least that region of the container that has the container opening, be placed in a clean chamber that separates it from a non-sterile surrounding environment.
To allow access for maintenance and repair work, and to observe the container treatment processes, for example the filling and closing process, it is customary to provide viewing windows in the separating walls that form an enclosure. It is important that a substantial portion of these separating walls be transparent.
The separating walls have mounting frames and panes. Although the panes are removable from the mounting frame, they are tightly connected to it using permanently elastic pane seals. The pane seals are connected to the mounting frame by adhesive bonds or by using special clamping profiles.
The pane seals and the sealing arrangements that use those seals for sealing a viewing window to a mounting frame are critical. These seals help ensure the sterility of the clean chamber.
Known pane seals and sealing arrangements have uncontrolled features, such as nooks, gaps, undercuts, and pockets. These uncontrolled features regularly form the starting point for contamination and/or soiling. Such features have thus far been unavoidable in the region of the pane seals, especially on the side of the pane seal that faces the clean chamber.
Pocket formation is encouraged by exposure to chemicals, high temperatures, and intensive air-flow. The risk of pocket formation increases over time, as relentless attacks on the adhesive bonds degrade the clamping effect intrinsic to the seal.
Adhesive bonds with clamping profiles for retaining the pane seals require a laborious and time-consuming assembly procedure. This is also true for assembly of seals that require adhesive bonds, which moreover are undesirable when replacing defective viewing windows or defective seals.
Known lip seals have a U-shaped profile for attachment. In these known lip seals, the U-shaped profile straddles the aperture edge surrounding an aperture of an enclosure in much the same way a rider straddles his horse. A reliable and, in particular, permanently gap-free attachment of the lip seal to the enclosure cannot be achieved with this seal.
Another known seal has an inflatable sealing profile that seals a transition between a door leaf and a frame surrounding the door leaf. When inflated, the seal develops a sickle-shaped sealing section that bears against the door leaf. These known sealing profiles are neither intended nor suitable for the peripheral sealing of an aperture closure and viewing window of an enclosure that forms a clean chamber.